1. Field of the Invention
The present invention relates generally to trolling motors. More specifically, the invention is an improved trolling motor which utilizes a unique structural configuration as well as noise reducing means to render the device extremely quiet.
2. Description of the Related Art
It is common for boaters to desire extremely quiet boat motors for several reasons. One reason for desiring a quiet motor is to avoid disturbing the surrounding environment or disrupting one's enjoyment of a day on the water. Fishermen generally desire a quiet boat motor to prevent disrupting the underwater environment of the fish which would likely scare them away.
A typical trolling boat motor is designed to run quietly. Trolling boat motors are generally fashioned such that there is an electric motor provided within a housing and a shaft which is connected to the motor at one end and to a propeller at its other end. These motors, although relatively quiet, do create noise which may disturb the marine environment.
Boat motors, and boat motor noise reduction methods have been the subject of prior patents. U.S. Pat. No. 2,756,713 issued on Jul. 31, 1956 to Kort discloses a method of and a means for reducing noises and vibrations produced by screw propellers of ships. Kort accomplishes its objectives by forming uniquely shaped nozzles around the propellers or modifying the shape of the hull of the ship. Kort does not disclose reducing motor noise by means as described in the present invention.
U.S. Pat. No. 2,877,733 issued on Mar. 17, 1959 to Harris discloses an electric steering and power control system for outboard motors. Harris discloses a motor which is displaced below the water line.
U.S. Pat. No. 3,845,839 issued on Nov. 5, 1974 to Eriksson discloses a device for use in a motor boat for damping the noise directly or indirectly produced by a motor. The device has a noise damping receptacle in the shape of a box which slides into the hull of the boat. Eriksson does not disclose reducing motor noise by means as described in the present invention.
U.S. Pat. No. 3,587,512 issued on Jun. 28, 1971 to Patterson discloses a boat with secondary propulsion means. The boat has a motor and propeller assembly mounted within the bow of the boat that can be raised and lowered when needed. Patterson does not teach or describe any means of connecting the motor and propeller.
U.S. Pat. No. 3,606,858 issued on Sep. 21, 1971 to Edwards et al. discloses a remotely steerable electric outboard motor which is placed below the water line. Edwards et al. teaches away from the present invention where the motor is placed above the water line.
U.S. Pat. No. 3,954,082 issued on May 4, 1976 to Roller et al. discloses a housing and sealing gasket enclosing an unsealed DC motor for submerged use in water. The invention in Roller et al. teaches away from the present invention, where the object is to have the motor displaced above the water line.
U.S. Pat. No. 4,293,304 issued on Oct. 6, 1981 to Sandstrom et al. discloses a flexibly mounted drive shaft for a ship. The orientation of the shafts and the fact that they are prevented from vibrating a significant amount renders the motor and propeller motion relatively quiet. Sandstrom et al. does not disclose reducing motor noise by means as described in the present invention.
U.S. Pat. No. 4,787,868 issued on Nov. 29, 1988 to Hoshiba et al. discloses an outboard motor drive having an improved arrangement for absorbing torsional vibrations and isolating the drive shaft from the vibrations. The vibrations are absorbed in some embodiments by an elastomeric sleeve, and in other embodiments by a viscous fluid. The patent issued to Hoshiba et al. does not disclose a means for reducing motor noise as in the present invention.
U.S. Pat. No. 5,169,349 issued on Dec. 8, 1992 to Hilbert discloses an electric trolling motor apparatus provided with a passage that protects a wire of a sonar unit which is connected to the motor. Hilbert does not disclose the placement of the trolling motor above the water line in addition to noise isolating means as in the present invention.
U.S. Pat. No. 5,336,119 issued on Aug. 9, 1964 to Lais et al. discloses a drive unit for relatively small water craft having a cylindrical underwater partial housing which carries, at one end, an electric motor, with which a propeller is arranged, at the other end, in such a way that it is seated on a shaft which is rotatably mounted in a parallel relationship with the motor output shaft. The motor output shaft and the propeller shaft are connected by a toothed belt drive. Lais does not disclose reducing motor noise by means as described in the present invention.
U.S. Pat. No. 5,389,746 issued on Feb. 14, 1995 to Moody discloses an acoustic isolation structure in the hull of a submarine to reduce noise generated by the submarine. Moody does not teach motor noise reduction methods as described in the present invention.
U.S. Pat. No. 5,597,245 issued on Jan. 28, 1997 to Meyerhoff discloses a propeller cavitation suppression system. The invention relates to a device for use with a ducted propeller system for suppressing gap cavitation between a moving rotor tip and a duct wall. Meyerhoff does not disclose motor noise reduction methods as in the present invention.
UK Patent No. 2,264,683 published on Sep. 8, 1993 discloses a vibration absorbing steering device for outboard motors. The device is designed to reduce vibrations that are typically transmitted to the drive shaft, the propeller, and the operator of the motor. The invention does not disclose noise reduction means as disclosed in the present invention.
Japanese Patent No. 63-246,257 Published on Oct. 13, 1988 discloses a method of reducing vibration energy effectively over a wide band of vibration by analyzing a detected vibration spectrum and vibration mode such as phase, then outputing vibration suppressing energy having phase shifted by 180 degrees corresponding to the magnitude of the respective vibrations.
Other patents which are generally related to the present invention are U.S. Pat. No. 2,848,884 (Gear) issued on Aug. 26, 1958 to Maude; U.S. Pat. No. 3,201,953 (Torque Limiting Device) issued on Aug. 24, 1965 to Firth; U.S. Pat. No. 3,424,287 (Yieldable Clutch) issued on Jan. 28, 1969 to Dreiding; and Russian Patent No. 850,509 published in August 1981.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus an improved trolling motor solving the aforementioned problems is desired.